Multidrug-Resistant Bacterial Infections in Solid Organ Transplant Candidates and Recipients

The impact of colonization by multidrug resistant bacteria on graft survival, risk of infection, and mortality in recipients of solid organ transplant: systematic review and meta-analysis

BACKGROUND

The Global increase in colonization by multidrug-resistant (MDR) bacteria poses a significant concern. The precise impact of MDR colonization in solid organ transplant recipients (SOTR) remains not well established.

OBJECTIVES

To assess the impact of MDR colonization on SOTR's mortality, infection, or graft loss.

METHODS AND DATA SOURCES

Data from PROSPERO, OVID Medline, OVID EMBASE, Wiley Cochrane Library, ProQuest Dissertations, Theses Global, and SCOPUS were systematically reviewed, spanning from inception until 20 March 2023. The study protocol was registered with PROSPERO (CRD42022290011) and followed the PRISMA guidelines. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, INTERVENTIONS, AND ASSESSMENT OF RISK OF BIAS: Cohorts and case-control studies that reported on adult SOTR colonized by Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), extended-spectrum β-lactamase (ESBL) or carbapenem-resistant Enterobacteriaceae. (CRE), or MDR-pseudomonas, and compared to noncolonized, were included. Two reviewers assessed eligibility, conducted a risk of bias evaluation using the Newcastle-Ottawa Scale, and rated certainty of evidence using the GRADE approach.

METHODS OF DATA SYNTHESIS

We employed RevMan for a meta-analysis, using random-effects models to compute pooled odds ratios (OR) and 95% confidence intervals (CI). Statistical heterogeneity was determined using the I2 statistic.

RESULTS

15,202 SOTR (33 cohort, six case-control studies) were included, where liver transplant and VRE colonization (25 and 14 studies) were predominant. MDR colonization significantly increased posttransplant 1-year mortality (OR, 2.35; 95% CI, 1.63-3.38) and mixed infections (OR, 10.74; 95% CI, 7.56-12.26) across transplant types (p < 0.001 and I2 = 58%), but no detected impact on graft loss (p 0.41, I2 = 0). Subgroup analysis indicated a higher association between CRE or ESBL colonization with outcomes (CRE: death OR, 3.94; mixed infections OR, 24.8; ESBL: mixed infections OR, 10.3; no mortality data) compared to MRSA (Death: OR, 2.25; mixed infection: OR, 7.75) or VRE colonization (Death: p 0.20, mixed infections: OR, 5.71).

CONCLUSIONS

MDR colonization in SOTR, particularly CRE, is associated with increased mortality. Despite the low certainty of the evidence, actions to prevent MDR colonization in transplant candidates are warranted.

Bioinspired peptides induce different cell death mechanisms against opportunistic yeasts

The management of fungal diseases imposes an urgent need for the development of effective antifungal drugs. Among new drug candidates are the antimicrobial peptides, and especially their derivatives. Here, we investigated the molecular mechanism of action of three bioinspired peptides against the opportunistic yeasts Candida tropicalis and Candida albicans. We assessed morphological changes, mitochondrial functionality, chromatin condensation, ROS production, activation of metacaspases, and the occurrence of cell death. Our results indicated that the peptides induced sharply contrasting death kinetics, of 6 h for RR and 3 h for D-RR to C. tropicalis and 1 h for WR to C. albicans. Both peptide-treated yeasts exhibited increased ROS levels, mitochondrial hyperpolarization, cell size reduction, and chromatin condensation. RR and WR induced necrosis in C. tropicalis and C. albicans, but not D-RR in C. tropicalis. The antioxidant ascorbic acid reverted the toxic effect of RR and D-RR, but not WR, suggesting that instead of ROS there is a second signal triggered that leads to yeast death. Our data suggest that RR induced a regulated accidental cell death in C. tropicalis, D-RR induced a programmed cell death metacaspase-independent in C. tropicalis, while WR induced an accidental cell death in C. albicans. Our results were obtained with the LD100 and within the time that the peptides induce the yeast death. Within this temporal frame, our results allow us to gain clarity on the events triggered by the peptide-cell interaction and their temporal order, providing a better understanding of the death process induced by them.

Gram-negative bacterial colonizations before bilateral lung transplant. The impact of 'targeted' versus 'standard' surgical prophylaxis

BACKGROUND

Infections are one of the most common causes of death after lung transplant (LT). However, the benefit of 'targeted' prophylaxis in LT recipients pre-colonized by Gram-negative (GN) bacteria is still unclear.

METHODS

All consecutive bilateral LT recipients admitted to the Intensive Care Unit of the University Hospital of Padua (February 2016-2023) were retrospectively screened. Only patients with pre-existing GN bacterial isolations were enrolled and analyzed according to the antimicrobial surgical prophylaxis ('standard' vs. 'targeted' on the preoperative bacterial isolation).

RESULTS

One hundred eighty-one LT recipients were screened, 46 enrolled. Twenty-two (48%) recipients were exposed to 'targeted' prophylaxis, while 24 (52%) to 'standard' prophylaxis. Overall prevalence of postoperative multi-drug resistant (MDR) GN bacteria isolation was 65%, with no differences between the two surgical prophylaxis (p = 0.364). Eleven (79%) patients treated with 'standard' prophylaxis and twelve (75%) with 'targeted' therapy reconfirmed the preoperative GN pathogen (p = 0.999). The prevalence of postoperative infections due to MDR GN bacteria was 50%. Of these recipients, 4 belonged to the 'standard' and 11 to the 'targeted' prophylaxis (p = 0.027).

CONCLUSIONS

The administration of a 'targeted' prophylaxis in LT pre-colonized recipients seemed not to prevent the occurrence of postoperative MDR GN infections.

Frequency and impact on renal transplant outcomes of urinary tract infections due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella species

Background

Enterobacterales are often responsible for urinary tract infection (UTI) in kidney transplant recipients. Among these, Escherichia coli or Klebsiella species producing extended-spectrum beta-lactamase (ESBL) are emerging. However, there are only scarce data on frequency and impact of ESBL-UTI on transplant outcomes.

Methods

We investigated frequency and impact of first-year UTI events with ESBL Escherichia coli and/or Klebsiella species in a prospective multicenter cohort consisting of 1,482 kidney transplants performed between 2012 and 2017, focusing only on 389 kidney transplants having at least one UTI with Escherichia coli and/or Klebsiella species. The cohort had a median follow-up of four years.

Results

In total, 139/825 (17%) first-year UTI events in 69/389 (18%) transplant recipients were caused by ESBL-producing strains. Both UTI phenotypes and proportion among all UTI events over time were not different compared with UTI caused by non-ESBL-producing strains. However, hospitalizations in UTI with ESBL-producing strains were more often observed (39% versus 26%, p = 0.04). Transplant recipients with first-year UTI events with an ESBL-producing strain had more frequently recurrent UTI (33% versus 18%, p = 0.02) but there was no significant difference in one-year kidney function as well as longer-term graft and patient survival between patients with and without ESBL-UTI.

Conclusion

First-year UTI events with ESBL-producing Escherichia coli and/or Klebsiella species are associated with a higher need for hospitalization but do neither impact allograft function nor allograft and patient survival.

An Emerging Issue: Carbapenem-Resistant Enterobacteriaceae in Solid-Organ Transplantation

OBJECTIVES

Bloodstream infections caused by carbapenem-resistant bacteria have increased globally. Solid-organ transplant recipients are more prone to these infections. This study aimed to compare the clinical courses of carbapenem-susceptible and carbapenem-resistant Enterobacteriaceae bloodstream infections and to identify risk factors for carbapenem resistance in solid-organ transplant recipients.

MATERIALS AND METHODS

For this retrospective descriptive study, data for solid-organ transplant recipients (age ≥18) treated from 2015 to 2022 were obtained from medical records. Enterobacteriaceaepositive blood culture was screened from laboratory data.

RESULTS

Among 72 patients, there were 100 bacteremia episodes. Patients included 40 kidney (55.6%), 21 liver (29.2%), 7 heart (9.7%), and 4 combined liver and kidney (5.6%) transplant recipients. Fifty-seven bacteremia episodes were recorded between 2015 and 2020, and 43 bacteremia episodes were recorded between 2020 and 2022. Carbapenem resistance was reported in 15.8% of patients before 2020, whereas this rate increased to 39.5% after 2020 (P = .007). Pitt bacteremia score ≥4 (P < .001), Charlson comorbidity index ≥4 (P = .021), chronic liver disease (P = .015), septic shock at admission (P = .001), hypotension at admission (P = .006), bacteremia episodes 48 hours after hospitalization (P = .004), hospitalization in the past 3 months (P = .004), and prior invasive procedure (P = .043) were significant factors for carbapenem resistance. Logistic regression analysis showed that bacteremia 48 hours after hospitalization (P = .002) and hospitalization in the past 3 months (P = .006) were independent risk factors.

CONCLUSIONS

Carbapenem resistance increased significantly over the years. Bacteremia 48 hours after hospitalization and hospitalization within the past 3 months were determined to be risk factors for carbapenem resistance. Carbapenem-resistant infections are still nosocomial infections. Patients should be hospitalized for as a short time as possible, and both patients and their physicians should follow infection control and prevention methods.

Approach to multidrug resistant infections in pediatric transplant recipients

Introduction

There is increasing recognition of infections due to multidrug-resistant Gram negative (MDRGN) bacterial infections among children undergoing solid organ and hematopoietic cell transplantation, which may be associated with morbidity and mortality.

Methods

We present two vignettes that highlight the clinical challenges of evaluation, management, and prevention of MDRGN bacterial infections in children prior to and after transplantation. The goal of this discussion is to provide a framework to help develop an approach to evaluation and management of these infections.

Results

Source control remains the utmost priority in management of MDR infections and is paired with antibiotic selection guided by in vitro susceptibilities, adverse effect profiles, and clinical response. Identification and confirmation of resistance can be challenging and often requires additional testing for recognition of complex mechanisms. Current antimicrobial approaches to MDRGN infections include use of novel agents, prolonged infusion, and/or combination therapy. We also discuss preventative efforts including infection control, antimicrobial stewardship, targeted pre-emptive or prophylactic treatment, and decolonization.

Discussion

The impact of MDRGN infections on patient and graft survival highlights the need to optimize treatment and prevention strategies.

A joint program of antimicrobial stewardship and hospital-acquired infection control to reduce healthcare-associated infections after kidney transplantation: The Hipomenes study

Infection is a common complication in kidney transplant recipients (KTRs). The usefulness of antimicrobial stewardship programs (ASP) and hospital-acquired infection control (HAIC) initiatives in the general inpatient population is well established. We performed a quasi-experimental study to evaluate a joint ASP/HAIC initiative focused on KTRs. A dedicated ASP team optimized antimicrobial prescriptions in consecutive KTRs during the intervention period (June 2015-March 2016). A multifaceted, evidence-based HAIC program was concurrently implemented. Results were compared with the preceding period (June 2014-March 2015). We included 96 and 100 KTRs in the intervention and preintervention periods, respectively. There was a reduction in the consumption of meropenem (rate ratio [RR]: 0.63; 95% confidence interval [CI]: 0.53-0.75; P <.0001), ceftazidime (RR: 0.31; 95% CI: 0.21-0.45; P <.0001), vancomycin (RR: 0.65; 95% CI: 0.53-0.8; P <.0001), and ciprofloxacin (RR: 0.66; 95% CI: 0.55-0.81; P <.0001) and an increase of fosfomycin (RR: 1.80; 95% CI: 1.17-2.76; P =.008) during the intervention period. The incidence of cystitis (RR: 0.30; 95% CI: 0.28-0.33; P <.001) and upper urinary tract infection (RR: 0.56; 95% CI: 0.33-0.95; P =.04) decreased. A specific ASP/HAIC initiative was effective in optimizing antimicrobial use and reducing the incidence of common bacterial infections among KTRs.

Rapid antimicrobial resistance detection methods for bloodstream infection in solid organ transplantation: Proposed clinical guidance, unmet needs, and future directions

Recent advances in antimicrobial resistance detection have spurred the development of multiple assays that can accurately detect the presence of bacterial resistance from positive blood cultures, resulting in faster institution of effective antimicrobial therapy. Despite these advances, there are limited data regarding the use of these assays in solid organ transplant (SOT) recipients and there is little guidance on how to select, implement, and interpret them in clinical practice. We describe a practical approach to the implementation and interpretation of these assays in SOT recipients using the best available data and expert opinion. These findings were part of a consensus conference sponsored by the American Society of Transplantation held on December 7, 2021 and represent the collaboration between experts in transplant infectious diseases, pharmacy, antimicrobial and diagnostic stewardship, and clinical microbiology. Areas of unmet need and recommendations for future investigation are also presented.

Investigating infectious outcomes in adult patients undergoing solid organ transplantation: A retrospective single-center experience, Paris, France

OBJECTIVES

This study described the demographic characteristics, clinical presentation, treatment, and outcomes of solid organ transplant recipients who were admitted to our center for infection. It also determined factors associated with a poor outcome, and compares early and late period infections.

METHODS

In this retrospective observational study, conducted at a tertiary care center in France between October 2017 and March 2019, infectious outcomes of patients with solid organ transplant where studied.

RESULTS

A total of 104 patients were included with 158 hospitalizations for infection. Among these 104 patients, 71 (68%) were men. The median age was 59 years old. The most common symptoms on admission were fever (66%) and chills (31%). Lower respiratory tract infections were the most common diagnosis (71/158 hospitalizations). Urinary tract infections were frequently seen in kidney transplant recipients (25/60 hospitalizations). One or more infectious agents were isolated for 113 hospitalizations (72%): 70 bacteria, 36 viruses and 10 fungi, with predominance of gram-negative bacilli (53 cases) of which 13 were multidrug-resistant. The most frequently used antibiotics were third generation cephalosporins (40 cases), followed by piperacillin-tazobactam (26 cases). We note that 25 infections (16%) occurred during the first 6 months (early post-transplant period). Patients admitted during the early post-transplant period were more often on immunosuppressive treatment with prednisone (25/25 VS 106/133) (p = 0.01), mycophenolic acid (22/25 VS 86/133) (p = 0.03), presented for an urinary tract infection (10/25 VS 25/133) (p = 0.04) or a bacterial infection (17/25 VS 53/133) (p = 0.01). Patients with later infection had more comorbidities (57/83 VS 9/21) (p = 0.03), cancer (19/83 VS 0/21) (p = 0.04) or were on treatment with everolimus (46/133 VS 0/25) (p = 0.001). During 31 hospitalizations (20%), patients presented with a serious infection requiring intensive care (n = 26; 16%) or leading to death (n = 7; 4%). Bacteremia, pulmonary and cardiac complications were the main risk factors associated with poor outcome.

CONCLUSION

Infections pose a significant challenge in the care of solid organ transplant patients, particularly those with comorbidities and intensive immunosuppression. This underscores the crucial importance of continuous surveillance and epidemiologic monitoring within this patient population.

Rise of the guardians: Gut microbial maneuvers in bacterial infections

AIMS

Bacterial infections are one of the major causes of mortality globally. The gut microbiota, primarily comprised of the commensals, performs an important role in maintaining intestinal immunometabolic homeostasis. The current review aims to provide a comprehensive understanding of how modulation of the gut microbiota influences opportunistic bacterial infections.

MATERIALS AND METHODS

Primarily centered around mechanisms related to colonization resistance, nutrient, and metabolite-associated factors, mucosal immune response, and commensal-pathogen reciprocal interactions, we discuss how gut microbiota can promote or prevent bacterial infections.

KEY FINDINGS

Opportunistic infections can occur directly due to obligate pathogens or indirectly due to the overgrowth of opportunistic pathobionts. Gut microbiota-centered mechanisms of altered intestinal immunometabolic and metabolomic homeostasis play a significant role in infection promotion and prevention. Depletion in the population of commensals, increased abundance of pathobionts, and overall decrease in gut microbial diversity and richness caused due to prolonged antibiotic use are risk factors of opportunistic bacterial infections, including infections from multidrug-resistant spp. Gut commensals can limit opportunistic infections by mechanisms including the production of antimicrobials, short-chain fatty acids, bile acid metabolism, promoting mucin formation, and maintaining immunological balance at the mucosa. Gut microbiota-centered strategies, including the administration of probiotics and fecal microbiota transplantation, could help attenuate opportunistic bacterial infections.

SIGNIFICANCE

The current review discussed the gut microbial population and function-specific aspects contributing to bacterial infection susceptibility and prophylaxis. Collectively, this review provides a comprehensive understanding of the mechanisms related to the dual role of gut microbiota in bacterial infections.

Colonization of extended-spectrum β-lactamase-producing Enterobacteriaceae does not affect subsequent infection and liver transplant outcomes: a retrospective observational cohort study

Objective

To investigate the colonization rate of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E), subsequent infections by ESBL-E and ESBL-producing gram-negative bacilli (ESBL-GNB), and the effect of ESBL-E colonization on clinical outcomes in liver transplantation (LT) recipients.

Methods

This is a retrospective cohort study that included patients who underwent LT at Shanghai Renji Hospital between July 2016 and December 2017. Rectal swabs from LT patients at the postoperative ICU enrollment were screened anonymously for ESBL-E carriage. Demographics data, laboratory indexes, operative complications, and clinical course information were also obtained. The extent of ESBL-E colonization, the subsequent infection rates of ESBL-E and ESBL-GNB, and the clinical outcomes were compared between ESBL-E colonized and non-colonized patients.

Results

In total, 496 liver transplant recipients (387 males) were included in this study. ESBL-E colonization was detected in 240 patients (48.4%). There was no significant difference between the rates of ESBL-E infection (5.8 vs. 3.1%, p = 0.143), Ischemia-reperfusion ≥ 3 (27.9 vs. 24.6%, p = 0.403), acute kidney injury (39.6 vs. 38.7%, p = 0.835), acute rejection (2.1 vs. 1.6%, p = 0.664), graft versus host reaction (1.3 vs. 1.2%, p = 0.937), duration of hospitalization (22 vs. 23 days, p = 0.568), 90-day mortality (7.1 vs. 4.7%, p = 0.262) and 1-year mortality (12.9 vs. 9.3%, p = 0.265) in patients with and without ESBL-E colonization. Though the ESBL-GNB infection rate was higher in ESBL-E colonized patients (12.1 vs. 6.6%, p = 0.037), multivariate analysis showed that ESBL-E colonization did not increase the risk of ESBL-GNB infection (Model 1: aOR 1.755, 95% CI: 0.911-3.380, p = 0.093; Model 2: aOR 1.556, 95% CI: 0.761-3.181, p = 0.226). The ESBL-producing bacteria spectrum of colonization was significantly different from that of infections occurring after LT, with only three colonization events leading to infection by the same pathogen identified.

Conclusion

ESBL-E colonization in liver transplant patients is not associated with ESBL-E infection, nor is it a risk factor for post-transplant ESBL-GNB infection. Additionally, ESBL-E colonization does not lead to worse prognoses when compared with non-colonized patients.

Clinical trial registration

Chinese Clinical Trial Registry, Identifier [ChiCTR2100043034].

Epidemiology and Prevention of Early Infections by Multi-Drug-Resistant Organisms in Adults Undergoing Liver Transplant: A Narrative Review

Invasive bacterial infections are a leading cause of morbidity and mortality after liver transplant (LT), especially during the first months after LT, and infections due to multi-drug-resistant organisms (MDRO) are increasing in this setting. Most of the infections in patients in intensive care unit arise from the endogenous microflora and, for this reason, pre-LT MDRO rectal colonization is a risk factor for developing MDRO infections in the post-LT. Moreover, the transplanted liver may carry an increased risk of MDRO infections due to organ transportation and preservation, to donor intensive care unit stay and previous antibiotic exposure. To date, little evidence is available about how MDRO pre-LT colonization in donors and recipients should address LT preventive and antibiotic prophylactic strategies, in order to reduce MDRO infections in the post-LT period. The present review provided an extensive overview of the recent literature on these topics, with the aim to offer a comprehensive insight about the epidemiology of MDRO colonization and infections in adult LT recipients, donor-derived MDRO infections, possible surveillance, and prophylactic strategies to reduce post-LT MDRO infections.

Opportunities for Antimicrobial Stewardship Interventions Among Solid Organ Transplant Recipients

Although antimicrobial stewardship programs have excelled over the past decade, uptake and application of these programs to special populations such as solid organ transplant recipients have lagged. Here, we review the value of antimicrobial stewardship for transplant centers and highlight data supporting interventions that are ripe for adoption. In addition, we review the design of antimicrobial stewardship initiatives, targets for both syndromic and system-based interventions.

Multidrug-resistant organisms in lung transplant: a narrative review

PURPOSE OF REVIEW

The purpose of this narrative review is presenting the current knowledge of multidrug-resistant (MDR) pathogens in lung transplant recipients, considering both Gram-positive and Gram-negative bacteria.

RECENT FINDINGS

Overall prevalence of Gram-negative pathogens has increased remarkably (4.33/1000 recipient-days) in solid organ transplant recipients, while the prevalence of Gram-positive bacteria seems to be decreasing (0.20 cases/100 transplant-years). In lung transplant, the prevalence of postoperative infections due to MDR-GN bacteria has been assessed between 31 and 57%, and the incidence of carbapenem-resistant Enterobacterales is between 0.4 and 20%, with a related mortality up to 70%. MDR Pseudomonas aeruginosa is common in lung transplant recipients with cystic fibrosis and may contribute to bronchiolitis obliterans syndrome. The prevalence of MDR Gram-positive bacteria is around 30% (predominantly Methicillin-resistant Staphylococcus aureus and Coagulase-negative staphylococcus).

SUMMARY

Survival after lung transplant, although lower than in other SOT, is increasing and currently at 60% at 5 years. This review highlights the potential clinical and social burden of postoperative infections in lung transplant recipients, and confirmed that a PI due to MDR bacteria negatively affects survival. A prompt diagnosis, prevention and management of these MDR pathogens should remain the cornerstone for higher goals of care.

Antibiotic stewardship implementation at the largest solid organ transplantation center in Asia: a retrospective cohort study

BACKGROUND

Using Antimicrobial stewardship programs (ASP) to monitor the use of antibiotics can lead to improved antibiotic use and reduced costs.

METHODS

This retrospective cohort study was done at Shiraz Organ Transplant Center, the largest transplant center in Asia. Antimicrobial use, cost, clinical outcomes, and antibiotic resistance pattern were evaluated before and after ASP.

RESULTS

This study included 2791 patients, 1154 of whom were related to the time before ASP and 1637 to the time after ASP. During the period of the research, a total of 4051 interventions were done. The use of all classes of antibiotics was significantly reduced by ASP, with 329 DDD/100PD before the intervention compared to 201 DDD/100PD after it (p = 0.04). In addition, the overall cost of antibiotics purchased was much lower after the ASP measures were implemented ($43.10 per PD) than before implementation of the ASP measures ($60.60 per PD) (p = 0.03). After the implementation of ASP, the number of MDR isolates was significantly reduced.

CONCLUSION

The results of our study showed that the implementation of ASP significantly reduced the number and costs of antibiotics and also the number of resistant pathogens, but did not affect the patients' length of stay.

Prediction models for carbapenem-resistant Enterobacterales carriage at liver transplantation: A multicenter retrospective study

BACKGROUND

Carbapenem-resistant Enterobacterales (CRE) colonisation at liver transplantation (LT) increases the risk of CRE infection after LT, which impacts on recipients' survival. Colonization status usually becomes evident only near LT. Thus, predictive models can be useful to guide antibiotic prophylaxis in endemic centres.

AIMS

This study aimed to identify risk factors for CRE colonisation at LT in order to build a predictive model.

METHODS

Retrospective multicentre study including consecutive adult patients who underwent LT, from 2010 to 2019, at two large teaching hospitals. We excluded patients who had CRE infections within 90 days before LT. CRE screening was performed in all patients on the day of LT. Exposure variables were considered within 90 days before LT and included cirrhosis complications, underlying disease, time on the waiting list, MELD and CLIF-SOFA scores, antibiotic use, intensive care unit and hospital stay, and infections. A machine learning model was trained to detect the probability of a patient being colonized with CRE at LT.

RESULTS

A total of 1544 patients were analyzed, 116 (7.5%) patients were colonized by CRE at LT. The median time from CRE isolation to LT was 5 days. Use of antibiotics, hepato-renal syndrome, worst CLIF sofa score, and use of beta-lactam/beta-lactamase inhibitor increased the probability of a patient having pre-LT CRE. The proposed algorithm had a sensitivity of 66% and a specificity of 83% with a negative predictive value of 97%.

CONCLUSIONS

We created a model able to predict CRE colonization at LT based on easy-to-obtain features that could guide antibiotic prophylaxis.

Multidrug-Resistant and Extended-Spectrum β-Lactamase Gram-Negative Bacteria in Bilateral Lung Transplant Recipients: Incidence, Risk Factors, and In-Hospital Mortality

BACKGROUND

In recent decades, the incidence of multidrug-resistant (MDR) and extended-spectrum β-lactamase (ESBL) gram-negative (GN) bacteria has increased progressively among lung transplantation (LT) recipients. A prompt diagnosis, prevention, and management of these pathogens remain the cornerstone for successful organ transplantation.

RESEARCH QUESTION

What are the incidence of MDR and ESBL GN bacteria within the first 30 days after LT and related risk of in-hospital mortality? What are the potential clinical predictors of isolation of MDR and ESBL GN bacteria?

STUDY DESIGN AND METHODS

All consecutive LT recipients admitted to the ICU of the University Hospital of Padua (February 2016-December 2021) were screened retrospectively. Only adult patients undergoing the first bilateral LT and not requiring invasive mechanical ventilation, extracorporeal membrane oxygenation, or both before surgery were included. MDR and ESBL GN bacteria were identified using in vitro susceptibility tests and were isolated from the respiratory tract, blood, urine, rectal swab, or surgical wound or drainage according to a routine protocol.

RESULTS

One hundred fifty-three LT recipients were screened, and 132 were considered for analysis. Median age was 52 years (interquartile range, 41-60 years) and 46 patients (35%) were women. MDR and ESBL GN bacteria were identified in 45 patients (34%), and 60% of patients demonstrated clinically relevant infection. Pseudomonas aeruginosa (n = 22 [49%]) and Klebsiella pneumoniae (n = 17 [38%]) were frequently isolated after LT from the respiratory tract (n = 21 [47%]) and multiple sites (n = 18 [40%]). Previous recipient-related colonization (hazard ratio [HR], 2.48 [95% CI, 1.04-5.90]; P = .04) and empirical exposure to broad-spectrum antibiotics (HR, 6.94 [95% CI, 2.93-16.46]; P < .01) were independent predictors of isolation of MDR and ESBL GN bacteria. In-hospital mortality of the MDR and ESBL group was 27% (HR, 6.38 [95% CI, 1.98-20.63]; P < .01).

INTERPRETATION

The incidence of MDR and ESBL GN bacteria after LT was 34%, and in-hospital mortality was six times greater. Previous recipient-related colonization and empirical exposure to broad-spectrum antibiotics were clinical predictors of isolation of MDR and ESBL GN bacteria.

Perioperative antibiotic stewardship in the organ transplant setting

BACKGROUND

Solid organ transplant (SOT) recipients can benefit from traditional antimicrobial stewardship (AMS) activities directed to improve judicious perioperative prescribing and management, but evidence is lacking. The aim of this expert opinion review is to provide an update on the current landscape of application of AMS practices for optimization of perioperative prophylaxis (PP).

METHODS

We reviewed the available literature on early postoperative infectious complications in SOT and PP management, on modified perioperative approaches in case of infection or colonization in recipients and donors and on AMS in transplantation PP.

RESULTS

SOT recipients are at high risk for early postoperative infectious complications due to the complexity of surgical procedures, severity of end stage organ disease, net state of immunosuppression in the posttransplant period and to the high risk for multidrug resistant organism. Moreover, SOT may be exposed to preservation fluid infections and expected or unexpected donor-derived infections. We summarize main factors to take into account when prescribing transplant PP.

CONCLUSION

Creating personalized PP to avoid unwanted consequences of antimicrobials while improving outcomes is an emerging and critical aspect in SOT setting. Further studies are needed to offer best PP tailored to SOT type and to evaluate interventions efficacy and safety.

Performance of two methods of carbapenem-resistant Enterobacterales surveillance on a kidney transplant ward: selective culture of and real-time PCR directly from rectal swabs

BACKGROUND

Infection with carbapenem-resistant Enterobacterales (CRE) is associated with a high mortality rate in kidney transplant recipients, and colonization with CRE is one of the major risk factors for CRE infection. There is, therefore, a need to improve the capacity to detect colonization with CRE among inpatients.

METHODS

In this prospective study, we compared the performance of real-time PCR for carbapenemase directly from rectal swabs with that of conventional CRE surveillance culture in all patients admitted to a kidney transplant ward between February 2019 and March 2020. Surveillance culture and real-time PCR were performed at admission and weekly until hospital discharge. Two perineum-rectal swabs were collected: one for culture and one for PCR.

RESULTS

We collected 905 paired samples for CRE surveillance from 399 patients, of whom 347 (87.0%) were kidney transplant recipients and 52 were waiting list patients. CRE was detected by culture and/or PCR in 75 patients (18.8%). Positivity for CRE was identified by PCR in 62 (15.5%) of the 399 patients and by culture in 55 (13.8%); 20 (5.0%) of the patients tested positive only on PCR, and 13 (3.3%) tested positive only on culture. The most common carbapenemase and species were, respectively, bla_KPC (in 85.5%) and Klebsiella pneumoniae (in 80.0%). Infection with CRE occurred in 21.6% of the colonized patients, those cases occurred only among kidney transplant recipients. None of the patients who tested negative on culture developed CRE infection.

CONCLUSION

In conclusion, the two methods are complementary and could be useful in a scenario of high CRE prevalence.

Challenges of Antimicrobial Resistance and Stewardship in Solid Organ Transplant Patients

Purpose of Review

Without effective antimicrobials, patients cannot undergo transplant surgery safely or sustain immunosuppressive therapy. This review examines the burden of antimicrobial resistance in solid organ transplant recipients and identifies opportunities for antimicrobial stewardship.

Recent Findings

Antimicrobial resistance has been identified to be the leading cause of death globally. Multidrug-resistant pathogens are associated with significant morbidity and mortality in transplant recipients. Methicillin-resistant S. aureus affects liver and lung recipients, causing bacteremia, pneumonia, and surgical site infections. Vancomycin-resistant enterococci is a nosocomial pathogen primarily causing bacteremia in liver recipients. Multidrug-resistant Gram-negative pathogens present urgent and serious threats to transplant recipients. Extended-spectrum beta-lactamase-producing E. coli and K. pneumoniae commonly cause bacteremia and intra-abdominal infections in liver and kidney recipients. Carbapenemase-producing Enterobacterales, mainly K. pneumoniae, are responsible for infections early-post transplant in liver, lung, kidney, and heart recipients. P. aeruginosa and A. baumannii continue to be critical threats. While there are new antimicrobial agents targeting resistant pathogens, judicious prescribing is crucial to minimize emerging resistance. The full implications of the COVID-19 global pandemic on antimicrobial resistance in transplant recipients remain to be understood. Currently, there are no established standards on the implementation of antimicrobial stewardship interventions, but strategies that leverage existing antimicrobial stewardship program structure while tailoring to the needs of transplant recipients may help to optimize antimicrobial use.

Summary

Clinicians caring for transplant recipients face unique challenges tackling emerging antimcirobial resistance. Coordinated antimicrobial stewardship interventions in collaboration with appropriate expertise in transplant and infectious diseases may mitigate against such threats.

Infection prevention requirements for the medical care of immunosuppressed patients: recommendations of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute

In Germany, guidelines for hygiene in hospitals are given in form of recommendations by the Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention, "KRINKO"). The KRINKO and its voluntary work are legitimized by the mandate according to § 23 of the Infection Protection Act (Infektionsschutzgesetz, "IfSG"). The original German version of this document was published in February 2021 and has now been made available to the international professional public in English. The guideline provides recommendations on infection prevention and control for immunocompromised individuals in health care facilities. This recommendation addresses not only measures related to direct medical care of immunocompromised patients, but also management aspects such as surveillance, screening, antibiotic stewardship, and technical/structural aspects such as patient rooms, air quality, and special measures during renovations.

Multidrug-resistant infections in solid organ transplant recipients: a focus on risk factors, prevention and treatment strategies

Solid organ transplantation is the best therapeutic option for patients with end-stage organ disease and, according to the data from international registries, there has been a steady increase in numbers and results. However, post-transplant infections remain a fearsome complication with, in the last decade, an increasing incidence of episodes due to antibiotic-resistant bacteria and opportunistic agents. In this paper, we summarize the most relevant and updated knowledge concerning infections from multidrug-resistant germs in solid organ transplant recipients, focusing on risk factors, treatment and prevention strategies, and antimicrobial pharmacokinetics relevant to this particular population of patients.

Antibiotic resistance in the patient with cancer: Escalating challenges and paths forward

Infection is the second leading cause of death in patients with cancer. Loss of efficacy in antibiotics due to antibiotic resistance in bacteria is an urgent threat against the continuing success of cancer therapy. In this review, the authors focus on recent updates on the impact of antibiotic resistance in the cancer setting, particularly on the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.). This review highlights the health and financial impact of antibiotic resistance in patients with cancer. Furthermore, the authors recommend measures to control the emergence of antibiotic resistance, highlighting the risk factors associated with cancer care. A lack of data in the etiology of infections, specifically in oncology patients in United States, is identified as a concern, and the authors advocate for a centralized and specialized surveillance system for patients with cancer to predict and prevent the emergence of antibiotic resistance. Finding better ways to predict, prevent, and treat antibiotic-resistant infections will have a major positive impact on the care of those with cancer.

Carbapenemase-producing Enterobacteriaceae in transplant patients

Carbapenemase-producing Enterobacteriaceae (CPE) are a serious public health concern and represent a major threat to immunocompromised hosts, including solid organ (SOT) and stem cell transplant (HSCT) recipients. Transplant patients are at particular risk of developing CPE colonization and/or infection due to their frequent exposure to prolonged courses of broad-spectrum antibiotics, altered immunocompetence and exposure to invasive procedures and immunosuppressive drugs. Gut colonization with CPE, in particular carbapenem-resistant Klebsiella pneumoniae, may occur before or after SOT in 2%-27% of patients and among 2%-9% of HSCT and has been associated with increased risk of developing CPE infections. In endemic areas, CPE infections occur in up to 18% of SOT, and HSCT patients can account for 5%-18% of all patients with CPE bacteraemia. Mortality rates up to 70% have been associated with CPE infections in both patient populations. The rapid initiation of an active therapy against CPE is advocated in these infections. Therapeutic options, however, are limited by the paucity of novel compounds that are currently available and by potential antibiotic-associated toxicities. Therefore, a multidisciplinary approach involving infection control and antimicrobial stewardship programmes still represents the mainstay for the management of CPE infections among transplant patients. The evidence for the use of prevention strategies such as CPE-targeted perioperative prophylaxis or gut decolonization is still scarce. Large, multicentre trials are required to better define prevention strategies and to guide the management of CPE infections in the transplant setting.

Risk Factors and Outcome of Multidrug-Resistant Infections after Heart Transplant: A Contemporary Single Center Experience

(1) Background: The aim of this study was to assess risk factors for multidrug-resistant/extensively drug-resistant (MDR/XDR) bacterial infections in heart transplant (HT) patients within three months after surgery and its impact on patient outcome. (2) Methods: Retrospective analysis of clinical, hemato-chemical, imaging, treatment and outcome data from 47 heart transplant recipients from January 2016 to December 2018. MDR/XDR infections were compared to non-MDR/XDR and noninfected patients. (3) Results: Most participants were males, median age 51 years: 35 (74.5%) developed an infection after HT; 14 (29.8%) were MDR/XDR infections. Prolonged hospital stay before HT correlated to MDR/XDR infection (p < 0.001). Sequential organ failure assessment (SOFA) score at sampling day was higher in MDR/XDR (p = 0.027). MDR/XDR were mostly blood-stream (BSI) (p = 0.043) and skin-soft tissue (SSTI) (p = 0.047) infections. Gram-negative infections were the most frequent, specifically carbapenem-resistant Klebsiella pneumoniae. Antibiotic therapy duration for MDR/XDR infections was longer (p = 0.057), eradication rate lower (p = 0.083) and hospital stay longer (p = 0.005) but not associated with a worse outcome. (4) Conclusions: MDR/XDR infections affect compromised HT recipients with a history of prolonged hospitalization, causing a lower rate of eradication and increased hospital stay. These frequently present as BSI and SSTI. We emphasize the need to prevent contamination of central venous catheters and the surgical site.

Solid organ transplant-specific antibiogram in a tertiary pediatric hospital in Canada

SOT recipients are more vulnerable to infections with antimicrobial-resistant organisms, and therefore, it may be useful for transplant centers to create transplant-specific antibiograms to direct empirical antimicrobial regimens and monitor trends in antimicrobial resistance. SOT-specific antibiograms were created using antimicrobial susceptibility data on isolates from 2012 to 2018 at The Hospital for Sick Children, Toronto, Ontario, Canada. The CLSI guidelines were followed to generate the antibiograms except that results from 2 years of data were pooled on a rolling basis to achieve larger sample sizes. The 3 most frequent organisms in one analysis period of the SOT antibiogram were Escherichia coli (average sample size ±standard deviation; n = 28.7 ± 3.8), Staphylococcus aureus (n = 27.8 ± 5.0), and Pseudomonas aeruginosa (non-CF) (n = 19.8 ± 8.8). For E.coli, susceptibilities in the SOT antibiogram were significantly lower than those in the hospital-wide antibiogram in 2017-2018 for ampicillin (27% vs 47%; p = .014), piperacillin/tazobactam (55% vs 88%; p < .001), cefotaxime (59% vs 89%; p < .001), ciprofloxacin (71% vs 88%; p = .007), and trimethoprim-sulfamethoxazole (41% vs 69%; p = .001), but not significantly different for aminoglycosides and meropenem. In the SOT antibiogram of E. coli, decreased susceptibility trend was confirmed in some antibiotics, including piperacillin/tazobactam (83% in 2012-2013 vs 55% in 2017-2018). At our center, the solid organ transplant-specific antibiogram revealed important differences in E. coli susceptibilities and trends in antimicrobial resistance. Developing a SOT antibiogram will assist in revising and improving empiric treatment guidelines as well as monitoring antimicrobial resistance in this population.

Cefiderocol-Based Combination Therapy for "Difficult-to-Treat" Gram-Negative Severe Infections: Real-Life Case Series and Future Perspectives

Cefiderocol is a new cephalosporin displaying against extensively resistant (XDR) Gram-negative bacteria. We report our experience with cefiderocol-based combination therapies as “rescue” treatments in immunocompromised or critically ill patients or in patients with post-surgical infections who had failed previous regimens. A total of 13 patients were treated from 1 September 2020 to 31 March 2021. In total, 5/13 (38%) patients were classified as critically ill, due to severe COVID-19 lung failure; 4/13 (31%) patients had post-surgical infections and 4/13 (31%) had severe infections in immunocompromised subjects due to solid organ transplantation (2/4) or hematological malignancy (2/4). Overall, 10/13 infections were caused by carbapenem-resistant Acinetobacter baumannii, one by KPC-positive ceftazidime/avibactam-resistant Klebsiella pneumonia and two by Pseudomonas aeruginosa XDR. Based on clinical, microbiological and hematobiochemical evaluation, cefiderocol was associated with different companion drugs, particularly with fosfomycin, high-dose tigecycline and/or colistin. Microbiological eradication was achieved in all cases and the 30-day survival rate was 10/13; two patients died due to SARS-CoV-2 lung failure, whereas one death was attributed to subsequent infections. No recurrent infections within 30 days were reported. Finally, we hereby discuss the therapeutic potential of cefiderocol and the possible place in the therapy of this novel drug.

Bacteriophage therapy as a treatment option for transplant infections

PURPOSE OF REVIEW

Since initial description of the successful use of intravenous bacteriophage therapy in the United States in 2017, there is widespread interest in using bacteriophage therapy for multidrug-resistant (MDR) infections.

RECENT FINDINGS

Recent published cases of bacteriophage therapy in transplant candidates and recipients are reviewed highlighting its safety and potential efficacy when used as an adjunct to systemic antibiotics for a variety of clinical indications. An overview of access to bacteriophage therapy in the United States is also provided.

SUMMARY

The reviewed cases form the basis for ongoing compassionate use of bacteriophage therapy in transplant candidates and recipients with life-threatening MDR infections until data from clinical trials are available to guide therapy.

Treatment of invasive IMP-4 Enterobacter cloacae infection in transplant recipients using ceftazidime/avibactam with aztreonam: A case series and literature review

Infections caused by carbapenemase-producing Enterobacteriaceae (CPE) are an emerging threat in both solid organ and stem cell transplant recipients. Invasive CPE infections in transplant recipients are associated with a high mortality, often due to limited therapeutic options and antibacterial toxicities. One of the most therapeutically challenging group of CPE are the metallo-β-lactamase (MBL)-producing Gram-negative bacteria, which are now found worldwide, and often need treatment with older, highly toxic antimicrobial regimens. Newer β-lactamase inhibitors such as avibactam have well-established activity against certain carbapenemases such as Klebsiella pneumoniae carbapenemases (KPC), but have no activity against MBL-producing organisms. Conversely, aztreonam has activity against MBL-producing organisms but is often inactivated by other co-existing β-lactamases. Here, we report four cases of invasive MBL-CPE infections in transplant recipients caused by IMP-4-producing Enterobacter cloacae who were successfully treated with a new, mechanism-driven antimicrobial combination of ceftazidime/avibactam with aztreonam. This novel antimicrobial combination offers a useful treatment option for high-risk patients with CPE infection, with reduced drug interactions and toxicity.

Treatment Strategies Against Diabetic Foot Ulcer: Success so Far and the Road Ahead

BACKGROUND

Diabetic foot ulcer (DFU) is one of the leading complications of type-2 diabetes mellitus. It is associated with neuropathy and peripheral arterial disease of the lower limb in patients with diabetes. There are four stages of wound healing, namely hemostasis phase, inflammatory phase, proliferative phase and maturation phase. In the case of DFU, all these stages are disturbed which lead to delay in healing and consequently to lower limb amputation. Conventional dosage forms like tablets, creams, ointments, gels and capsules have been used for the treatment of diabetic foot ulcer for many years.

INTRODUCTION

In this review, the global prevalence as well as etiopathogenesis related to diabetic foot ulcer have been discussed. The potential role of various synthetic and herbal drugs, as well as their conventional dosage forms in the effective management of DFU have been discussed in detail.

METHODS

Structured search of bibliographic databases from previously published peer-reviewed research papers was explored and data has been represented in terms of various approaches that are used for the treatment of DFU.

RESULTS

About 148 papers, including both research and review articles, were included in this review to produce a comprehensive as well as a readily understandable article. A series of herbal and synthetic drugs have been discussed along with their current status of treatment in terms of dose and mechanism of action.

CONCLUSION

DFU has become one of the most common complications in patients having diabetes for more than ten years. Hence, understanding the root cause and its successful treatment is a big challenge because it depends upon multiple factors such as the judicious selection of drugs as well as proper control of blood sugar level. Most of the drugs that have been used so far either belong to the category of antibiotics, antihyperglycaemic or they have been repositioned. In clinical practice, much focus has been given to dressings that have been used to cover the ulcer. The complete treatment of DFU is still a farfetched dream to be achieved and it is expected that combination therapy of herbal and synthetic drugs with multiple treatment pathways could be able to offer better management of DFU.

Donor-derived vancomycin-resistant enterococci transmission and bloodstream infection after intestinal transplantation

BACKGROUND

Transplant recipients are at high risk for infections. However, donor-recipient transmission of multidrug-resistant organisms (MDROs) remains mostly unaddressed in the protocols of pre-transplant infection and colonization screening. Vancomycin-resistant enterococci (VRE) are MDROs that colonize the gastrointestinal tract and are associated with a significant burden of disease. Besides the high mortality of invasive VRE infections, chronic colonization leads to costly isolation measures in the hospital setting. Whereas most post-transplantation VRE infections are endogenous and thus preceded by colonization of the recipient, conclusive evidence of VRE transmission via allograft in the context of intestinal transplantation is lacking.

CASE PRESENTATION

We describe a donor-derived VRE infection after intestinal transplantation including small bowel and right hemicolon. The recipient, a 54-year old male with history of mesenteric ischemia and small bowel perforation due to generalized atherosclerosis and chronic stenosis of the celiac trunk and the superior mesenteric artery, developed an intra-abdominal infection and bloodstream infection after transplantation. VRE isolates recovered from the patient as well as from the allograft prior to transplantation were analyzed via whole genome sequencing. Isolates showed to be genetically identical, thus confirming the transmission from donor to recipient.

CONCLUSIONS

This case underlines the relevance of donor-recipient VRE transmission and invasive infection in the context of intestinal transplantation, highlighting the need for preoperative MDRO screening that facilitates the prompt and effective treatment of possible infections as well as the timely establishment of contact precautions to prevent further spread.

Surgical site infection after liver transplantation in the era of multidrug-resistant bacteria: what new risks should be considered?

Surgical site infection (SSI) is a frequent infection site after liver transplantation (LT), and multidrug-resistant bacteria are common agents of those infections. This study aimed to analyze risk factors for SSI, including SSI caused by a multidrug-resistant microorganism (MDRO) after LT. We performed a cohort study of patients who underwent an LT from 2010 to 2018. The outcomes were SSI and SSI caused by MDRO. We analyzed features related to surgical procedure, patients' characteristics, and post-LT intercurrence. Surveillance for carbapenem-resistant Enterobacteriaceae (CRE), vancomycin-resistant Enterococcus (VRE), and carbapenem-resistant Acinetobacter baumannii (CRAB) was performed through rectal swab at the LT admission and weekly until hospital discharge during all study periods. SSI was identified in 30.1% (229/762) of LTs. We observed a decline in the SSI rate from 37.5% in 2014 to 16.7% in 2018 (P 0.02). SSI caused by MDRO occurred in 109 (14.3%) patients. Klebsiella pneumoniae was the most common agent of both SSI and SSI caused by MDRO. The pre-LT colonization was 98 (12.9%) by CRE, 73 (9.6%) by VRE, and 28 (3.7%) by CRAB. Risk factors for SSI caused by MDRO identified were dialysis after LT (P 0.01), CRAB acquisition before LT (0.03), and CRE acquisition before LT (P 0.004); use of adjusted prophylaxis by MDRO risk was the only protective factor identified (P 0.01). MDROs were frequent agents of SSI after LT, and the carbapenem-resistant Gram-negative colonization before LT increased the risk of SSI by these agents.

Multidrug-Resistant Gram-Negative Bacteria Decolonization in Immunocompromised Patients: A Focus on Fecal Microbiota Transplantation

Antimicrobial resistance is an important issue for global health; in immunocompromised patients, such as solid organ and hematological transplant recipients, it poses an even bigger threat. Colonization by multidrug-resistant (MDR) bacteria was acknowledged as a strong risk factor to subsequent infections, especially in individuals with a compromised immune system. A growing pile of studies has linked the imbalance caused by the dominance of certain taxa populating the gut, also known as intestinal microbiota dysbiosis, to an increased risk of MDR bacteria colonization. Several attempts were proposed to modulate the gut microbiota. Particularly, fecal microbiota transplantation (FMT) was successfully applied to treat conditions like Clostridioides difficile infection and other diseases linked to gut microbiota dysbiosis. In this review we aimed to provide a look at the data gathered so far on FMT, focusing on its possible role in treating MDR colonization in the setting of immunocompromised patients and analyzing its efficacy and safety.

Antimicrobial stewardship in transplant patients

PURPOSE OF REVIEW

To provide an update on the current landscape of antimicrobial stewardship in solid organ transplant (SOT) recipients.

RECENT FINDINGS

Constructing personalized antimicrobial prescribing approaches to avoid untoward consequences of antimicrobials while improving outcomes is an emerging and critical aspect of transplant medicine. Stewardship activities encompassing the specialized interests of transplant patients and programs are evolving. New literature evaluating strategies to optimize antimicrobial agent selection, dosing, and duration have been published. Additionally, consensus guidance for certain infectious clinical syndromes is available and should inform institutional clinical practice guidelines. Novel metrics for stewardship-related outcomes in transplantation are desperately needed. Though exciting new molecular diagnostic technologies will likely be pivotal in the care of immunocompromised patients, optimal clinical adaptation and appropriate integration remains unclear. Important studies understanding the behaviors influencing antimicrobial prescribing in organizational transplant cultures are needed to optimize interventions.

SUMMARY

Consequences of antimicrobial use, such as Clostridiodes difficile and infections with multidrug-resistant organisms disproportionately affect SOT recipients and are associated with poor allograft and patient outcomes. Application of ASP interventions tailored to SOT recipients is recommended though further studies are needed to provide guidance for best practice.

Carbapenemase-producing organisms in solid organ transplantation

PURPOSE OF REVIEW

Carbapenem-resistant enterobacteriaceae (CRE) are a critical healthcare threat. Infections caused by CRE disproportionately affect transplant patients. Retrospective case studies suggest that up to 10% of transplant recipients develop a CRE infection. The current literature is reviewed with a particular focus on transplant-specific implications.

RECENT FINDINGS

There are specific risks inherent to transplant recipients that result in an elevated risk for CRE carriage and subsequent infection. Additionally, the manifestations of these infections are dependent on the specific transplant type. The optimal treatment of CRE infections in transplant recipients has not been defined.

SUMMARY

A reduction in the regional community CRE burden can lead to a secondary reduction in their occurrence within vulnerable transplant populations. Therefore, core principles of antibiotic stewardship and infection control within all levels of the healthcare system remains the most effective strategy for addressing the current health crisis. Simultaneously, an integrated approach to risk stratification and an approach to treatment is postulated for management of CRE infection within the solid-organ transplant population.

Health Care-Associated Infection in Solid Organ Transplant Recipients

BACKGROUND

Health care-associated infection (HAI) represent a global health problem with an increase in hospital stays, deaths, and monetary costs. Recipients of solid organ transplants are a population at risk. The objectives of the study were to characterize the incidence of HAI in renal and hepatic transplant recipients as well as to compare them with the population without transplants in intensive care units (ICU).

METHODS

The data on the incidence of HAI, localization, microorganisms, and demographics were taken from the patients admitted between the years 2013 to 2018 (n = 4307) from the registration of the Project for the Reduction of Nosocomial Infection in Intensive Care Units. The variables were compared with those of renal transplant (n = 96) and liver transplants (n = 68) recipients.

RESULTS

Renal transplant recipients showed 26% incidence of HAI. The most frequent were surgical site infection (SSI), urinary tract infection, and primary bacteremia; the most frequent microorganism was Staphylococcus spp, mortality 3.8%. Liver transplant recipients showed 41% incidence of HAI. The most frequent were tracheobronchitis associated with mechanical ventilation, SSI, and primary bacteremia; the most frequent microorganism was Staphylococcus spp, mortality 37%. The population without transplants in the ICU showed 17% incidence of HAI. The most frequent were respiratory infections associated with mechanical ventilation, primary bacteremia, and SSI; the most frequent microorganism was Acinetobacter spp, mortality 21%.

CONCLUSIONS

HAI in recipients of solid organ transplants (renal and hepatic) have a higher incidence than in a population without transplants. The location and causal microorganisms have particularities that must be taken into account for the development of prevention protocols.

Clinical outcomes of ceftazidime-avibactam in lung transplant recipients with infections caused by extensively drug-resistant gram-negative bacilli

Background

Infections produced by extensively drug-resistant (XDR) gram-negative bacilli (GNB) in solid organ transplant (SOT) are an important cause of morbidity and mortality. Ceftazidime/avibactam (CAZ-AVI) is a novel β-lactam/β-lactamase combination antibiotic with anti-GNB activity, but experience in real clinical practice with CAZ-AVI in lung transplant (LT) recipients is limited.

Methods

We conducted a retrospective study of patients with XDR-GNB infection who received at least 3 days of CAZ-AVI in the Department of Lung Transplantation Between December 2017 and December 2018 at China-Japan friendship hospital (CJFH). The general information, clinical manifestations, laboratory examinations, treatment course, and outcomes were summarized.

Results

A total of 10 patients who underwent LT at our center were included. They were all males with a mean age 51 years. Infections after LT included pneumonia and/or tracheobronchitis [n=9; 90% (9/10)], cholecystitis and blood stream infection (BSI) (n=1, patient 8). In these 10 LT recipients, the incidence of various airway complications was 70% (7/10). Carbapenem-resistant Klebsialla pneumoniae (CRKP) was the predominant pathogen, being detected in 9 patients. Multilocus sequence typing (MLST) analysis showed that all 9 CRKP isolates belonged to ST11. Six patients (6/10, 60%) started CAZ-AVI as salvage therapy after a first-line treatment with other antimicrobials. CAZ-AVI was administered as monotherapy or in combination regimens in 20% (2/10) and 80% (8/10) of patients respectively. There were no difference in temperature before and after CAZ-AVI treatment (P>0.05). White blood cell (WBC) at 7 days, and procalcitonin (PCT) at 7 days and 14 days significantly dropped (P<0.05). After 7-14 days of CAZ-AVI treatment, the PaO₂/FiO₂ratio (P/F ratio) significantly improved (P<0.05). Nine patients (9/10, 90%) obtained negative microbiologic culture of CRKP/CRPA, with a median time to was 6.7 days (range, 1-15 days). However, 5 patients (5/10, 50%) had relapse of CRKP/CRPA infections in the respiratory tract regardless of whether negative microbiologic culture was obtained or not. The 30-day survival rate was 100%, and the 90-day survival rate was 90% (1/10). No severe adverse events related to CAZ-AVI occurred.

Conclusions

CAZ-AVI treatment of CRKP/ CRPA infection in LT recipients was associated with high rates of clinical success, survival, and safety, but recurrent CRKP/CRPA infections in the respiratory tract did occur.

Predictors of mortality in solid organ transplant recipients with bloodstream infections due to carbapenemase-producing Enterobacterales: The impact of cytomegalovirus disease and lymphopenia

Treatment of carbapenemase-producing Enterobacterales bloodstream infections in solid organ transplant recipients is challenging. The objective of this study was to develop a specific score to predict mortality in solid organ transplant recipients with carbapenemase-producing Enterobacterales bloodstream infections. A multinational, retrospective (2004-2016) cohort study (INCREMENT-SOT, ClinicalTrials.gov NCT02852902) was performed. The main outcome variable was 30-day all-cause mortality. The INCREMENT-SOT-CPE score was developed using logistic regression. The global cohort included 216 patients. The final logistic regression model included the following variables: INCREMENT-CPE mortality score ≥8 (8 points), no source control (3 points), inappropriate empirical therapy (2 points), cytomegalovirus disease (7 points), lymphopenia (4 points), and the interaction between INCREMENT-CPE score ≥8 and CMV disease (minus 7 points). This score showed an area under the receiver operating characteristic curve of 0.82 (95% confidence interval [CI] 0.76-0.88) and classified patients into 3 strata: 0-7 (low mortality), 8-11 (high mortality), and 12-17 (very-high mortality). We performed a stratified analysis of the effect of monotherapy vs combination therapy among 165 patients who received appropriate therapy. Monotherapy was associated with higher mortality only in the very-high (adjusted hazard ratio [HR] 2.82, 95% CI 1.13-7.06, P = .03) and high (HR 9.93, 95% CI 2.08-47.40, P = .004) mortality risk strata. A score-based algorithm is provided for therapy guidance.

Drug screening of rhodanine derivatives for antibacterial activity

Introduction: Bacteriological infections are a major risk to human health. These include all hospital and public-acquired infections. In drug discovery, rhodanines are privileged heterocyclic frameworks. Their derivatives possess strong anti-bacterial activity and some of them have shown potent activity against multidrug-resistant pathogens, both under in vitro and in vivo conditions. To treat multi-drug resistant pathogens, the development of novel potent drugs, with superior anti-bacterial efficacy, is paramount. One avenue which shows promise is the design and development of novel rhodanines.Areas covered: This review summarizes the status on rhodanine-based derivatives and their anti-bacterial activity, based on published research over the past six years. Furthermore, to facilitate the design of novel derivatives with improved functions, their structure-activity relationships are assessed with reference to their efficacy as anti-bacterial agents and their toxicity.Expert opinion: The pharmacological activity of molecules bearing a rhodanine scaffold needs to be very critically assessed in spite of considerable information available from various biological evaluations. Although, some data on structure-activity relationship frameworks is available, information is not adequate to optimize the efficacy of rhodanine derivatives for different applications.

Carbapenem-resistant Klebsiella pneumoniae infection causing rupture of graft artery in solid organ recipients: Case report and review of literature

RATIONALE

Donor-derived bacterial infection is a rare cause of morbidity after solid organ transplantation (SOT) but associated with significant morbidity and mortality, deaths caused by carbapenem-resistant Klebsiella pneumoniae (CRKP) infection account for a considerable proportion of postoperation mortality rate in liver and kidney recipients. The arterial rupture as a result of fungal arteritis is occasionally described, while the rupture of graft vascular anastomosis after SOT due to donor-derived CRKP infection is rarely reported.

PATIENTS CONCERNS

We reported 1 patient with donor-derived CRKP infection following liver transplantation and 2 patients following renal transplantation (1 liver and 2 kidneys were from the same donor), who experienced sudden abdominal pain and abdominal hemorrhage almost at the same time after organ transplantation.

DIAGNOSIS

The patients were diagnosed as graft arteries rupture due to corrosion caused by CRKP infection based on computed tomography scan, blood culture, laparotomy, and pulse-field gel electrophoresis.

INTERVENTIONS

Anti-shock treatment, exploratory laparotomy, broad-spectrum antibiotics, and abdominal puncture and drainage were given.

OUTCOMES

The liver recipient survived as well as the liver graft, still under treatment of multiple abdominal infections. The 2 renal recipients were alive after resection of the renal grafts and underwent hemodialysis.

LESSONS

Rupture of graft artery should be foreseen when donor-derived CRKP infection was confirmed and broad-spectrum antibiotics and other interventions need to be considered.